Not to sell Tart short (it is quite good), but it's "just" a wrapper around Virtualization.framework with a few extra pieces. This is the kind of thing that Codex driven by experts _should_ be able to build very easily.
That said, I've been free-riding on tart because they've often surfaced issues I needed to address. Free riders like me are possibly the reason these companies can't make their own way.
Long term: they now have experienced dev(s?) to build their next products and features
But someone with the knowledge to guide an AI will have more success than someone without, at least today. I don’t think that will necessarily be true in a year or two.
"Hey guys, make our agents verify tool use before responding to the user. See you in 2 months. Here's 2$b"